Schaeffler Automotive Aftermarket GmbH & Co. oHG · Germany

Ventiltriebkomponenten

• Pages: 44
• Format: DIN A-4

Publisher: Schaeffler Automotive Aftermarket GmbH & Co. oHG

Valve Train Components

Internal combustion engines require cyclic supply of fresh air and the exhaust air produced during combustion must be removed. In a 4-stroke combustion engine, the intake of fresh air and removal of exhaust air is called charge exchange. In the course of several charge exchange cycles, the cylinder control devices (inlet and outlet ports) are periodically opened and closed by shut-off devices (intake and exhaust valves). Shut-off devices fulfil special tasks. They have to: - clear the largest possible opening diameter; - perform opening and closing processes rapidly; - have streamlined design to minimize pressure loss; - ensure effective sealing when closed; - provide advanced durability characteristics.

With mechanical valve lash adjustment components, valve play has to be set manually during initial installation and re-adjusted at regular intervals by means of adjusting screws and shims. In parallel with mechanical solutions, automatically controlled hydraulic valve lash adjustment mechanisms have been developed, where overlap variation of the lift curves is reduced for all operating conditions of the engine over its entire service life, thereby ensuring consistently low exhaust emissions. The consequences of insufficient or excessive valve clearance range from noise emission in the valve train to a total engine failure. No less important are the detrimental effects on the environment due to poor exhaust emission behaviour. The following summary gives an outline of potential damage caused by insufficient or excessive valve lash.

• Pages: 44
• Format: DIN A-4

Publisher: Schaeffler Automotive Aftermarket GmbH & Co. oHG

气门机构零部件

• Pages: 15
• Format: DIN A-4

Publisher: Schaeffler Trading (Shanghai) Co., Ltd.